And wreckage found 1.2 miles away from the departure site doesn’t sound to me like LOC soon after TDP and before Vy was established - the critical time if ground refs were lost before stabilising airspeed had been established.
It seems unlikely the concrete departure helipad was not pretty well lit too, which would have reduced the chance of pilot disorientation before transition. This was a permanent base of a wealthy owner, after all. And the pilot had just successfully flown in there.
So seems to me early fingers pointing to some sort of mechanical failure - with the tail being the focus.